How is nuclear power produced?

Before we start the discussion on whether nuclear energy can have a positive or negative impact on our energy needs, it is very important to actually understand how nuclear power is produced. According to research conducted by the Nuclear Energy Institute, 30 countries around the world have operational nuclear reactors (around 450 in total) and over 60 are currently under construction. Not only that, but nuclear energy provides around 12% of the world's electricity according to a worldwide study conducted by Mycle Schneider and his colleagues for the World Nuclear Industry Report 2016. For many countries nuclear energy contributes towards a large chunk of electricity consumption, whereas for others it is not that substantial - 75% of France's electricity is generated through nuclear power but for India the figure is only 2% (see the figure below).

  Nuclear power production worldwide 

Often our understanding of nuclear energy is shaped by what we see in the media and through popular culture e.g. Hollywood films and TV adverts (Gamson and Modigliani 1989). We all remember cartoons like Dexter's Laboratory which showed how nuclear energy is made by a touch of a button or Marvel films which show bubbling cylinders of Uranium.  Whether we realise it or not, such representations have given many people (including myself before this blog) a very simplistic view of what nuclear energy is and how it is produced. Let's change that!

How is nuclear energy produced?

The crucial element in producing nuclear power is uranium. A silvery-white metal ore, uranium is a radioactive substance which is mined underground and is predominantly found in parts of Australia, Kazakhstan and Russia. The key advantage of using uranium is that it is quite abundant across the world, unlike coal and oil reserves which are seen to be dwindling in volume. In fact, a study by Smith (2006) has shown that are around 10 million tonnes of uranium which are classified as being 'undiscovered resources' - resources that have not even been explored yet. Once uranium has been mined, it is turned into small pellets that can be used to generate electricity. Each small pellet, which is generally the size of a peanut, can generate as much power as 800kg of coal (EDF energy research). 

All the magic then happens in the nuclear reactors - the commonly used ones are called Pressurised Water Reactors (PWRs) which can be seen below:

Different components in a nuclear power reactor 

Neutrons are fired at the uranium isotope (Uranium 235) which makes it unstable. When that happens, the uranium atom splits which causes the release of more neutrons which collide with other particles to create a chain reaction. These splitting atoms, as the diagram below shows, creates a considerable amount of heat energy which is needed to create electricity down the pipeline. The process through which the uranium atom splits is known as nuclear fission, and according to a MIT study by John Deutch and Ernest Moniz in 2003, the energy released by the fission of one kilogram of uranium is typically equivalent to the energy released by around 22,000 kilograms of coal. 

How an Uranium atom splits

Once enough heat energy has been produced, water is then passed into the vessel to allow it to heat to around 300 degrees. This heated water is then passed through to the steam generator and turbines which cause this water to turn into steam so that it can turn the turbines to produce electrical energy. An electromagnetic field then turns this steam into electrical energy which is then transmitted to the transformer so that the electricity can be allocated to where it is needed e.g. houses and factories.  Phew! That was a long process.  Since the first phase of nuclear reactors in the 1940s, Stoneham (2010) explains how technological developments have made nuclear energy production more efficient over time as laboratory research has enabled scientists to make sure that heat loss is reduced in nuclear reactors. 

If you would like to see nuclear power in action, have a look at this clip from the BBC program 'Bang Goes The Theory' where the presenter explores a reactor core in Austria: